Automatic and manual control of aircraft



Fb. 17, 1953 A STALKE 2,628,793

AUTOMATIC AND MANUAL CONTROL OF AIRCRAFT Filed 001,. 3, 1946 2SHEETSSHEET l x i, I

ill] I:

w [66 INVENTOR.

BY Ma. 51211.,

AT TORNEYS Feb. 1953 E. A. STALKER 2,628,793

AUTOMATIC AND MANUAL CONTROL OF AIRCRAFT Filed Oct. 5, 1946 2'Sl-IEETSSHEET 2 IN V EN TOR.

ATTORNEYS Patented Feb. 17, 195 3 OFFICE AUTOMATIC ANDMANUAL CONTROL OFAIRCRAFT Edward A. Stalker, Bay City, Mich.

A plication October a, 1946, Serial No. 701,024

-3 Claims. l

. This invention relates to aircraft and more particularl to means orautomaticall controlling such craft.

An object of the invention is to provide a con trol system for anaircraft which operates automatically in response to the relative windcondition and restores the aircraft to a balanced eondition of flightfrom an unbalanced condition in which side slip is present.

Another object of this invention is to provide mea s automaticallycontrolling a flight control function of the aircraft whose operation isinterrupted or disabled when the steering control is moved awa from itsneutral position.

C'J'ther objects and advantages will appear from the followingdescription, the accompan in drawings and the appended "claims.

In the drawings y Fig. 1 is a fragmentary top plan viewof an aircraftconstructed in accordance with the present invention;

Fig. 2 is a fragmentary schematic view of the control mechanism lookingforward from the pi-l-ots position;

Fig. his :a fragmentary view of the control mechanism looking laterallyon line 3'3 in Fig. 2;

I Fig. 4 is a section through the valve case alon the line 1+4 of Fig;3;

Fig. 5 is a vertical section and fragmentary through the ing along line5:5 o Fig. 1;

rig; 6 is a top plan view or a win and V Fig. '1 "is a-s-ecticn alonglih'e T or Fig. 6 with the air pressure distribution thereon indicatedfor two conditions of flight.

'When an airplane is flying along a straight course and it is rolled bysome disturbing force, the dihedial angle in the wings brings into layarestcring moment which returns the airplane to 1eve1 flight if thestick or steering control is in lateral rleutrar If; however, the pilotbanks the hhplaiie and pursues a curved flight path; the it plane willnot return to a 1-eve1 position (if the wines Wheh the stick isneutralized but will continue to fly in a curve.

2 pilot is unable to see the horizon because of inclement weather.

The aircraft according to this invention will automatically return to aproper condition of flight when the pilot ceases forcing the airplaneinto the maneuver. 'Ihus if the pilot forces the airplane to make a turnwith or without side= slip, the airplane will return to a level attitudefor the span of the wings as soon as he ceases to force this maneuver byreturning the stick to neutral. The attitude of the aircraft long-itudinally may be anything desired as this has no effect on the properfunctioning of the present in vention.

When an airplane is banked as in a turn; newtralizing thepilots stickdoes not restore the air-= plane to a horizontal attitude. The stick bemoved off center and then neutralized just bepilot to properly right theaircraft when the horizon is not visible.

This invention discloses a simple automatic means of righting theaircraft when the stick or other control is returned to neutral whichfunctions without reference to the horizon and which does vnot requirethe maneuver as above described In the drawings the airplane is showngener ally at It having the wings I2 and fuselage Ml The wings areequipped withlfiaps l6 and 18 for varying the lift of the wings.

In the nose surface of the fuselage are the holes 20 and 22 which arethus located in aposttion spaced a substantial distance from the cam terof gravity of the aircraft and at points with respect to which there isa substantial differ ence of velocity of the relative wind during theturning of the aircraft so as to be sensitive to such turning. Tubes 24and 26 connect each hole respectively to opposite sides of the pressure"re sponsive device 30 which can move the flaps dif ferentially inresponse to a difference of air pressure between the two holes; Thisprovides a control which is sensitive to dissimilar ressures at the noseof the plane, and thus to a conditioh of directional instability, whichchanges the lift of the Wings differentially and in the proper directionto right the aircraft as long as the hcis are subject to such dissimilarpressures.

The pilot controls the airplane by means of the stick 3| which istiltable laterally about thea xis of the tube 32 supported in bearings34 and 36 for actuating the elevator. The tube 38 extends rearward fromthe lower end of the stick to actuate the elevator. The ailerons I6 andI8 are moved by the arms 40 and 4| actuated by bellcranks 42 and 43,rods 44 and 46, the latter attaching to the parallel levers 50 and 52respectively. These levers are rotatably supported at centers 54 and 56on the support rod 66 which can slide laterally in the bearings 62 and63. The upper ends of the levers 50 and 52 are connected by the links 66and 67, and pin 68 to the arm 69 on the torque tube 32.

In straight flight the centers 54 and 56 of the levers 50, 52 aremaintained in a centered position by the jack I connected to the supportrod 60 and under the control of the pressures from the holes 20 and 22in the fuselage nose. Then operation of the stick laterally moves theailerons to roll the airplane. As will be described subsequently whenthe stick is moved laterally ofi neutral, the pressures from holes 20and 22 are unable to influence the aileron movement because valve 28 isclosed to their flow.

If the stick is in neutral the pressures from the holes 20 and 22 reachthe bellows 86 which has an annular cross-section. The pressure fromtube 22 enters the air-tight casing 82 in which the bellows are sealedwhile the pressure from tube 20 enters the interior of the bellows. Adifference in pressure will therefore cause the bellows to move rod 84articulated to movable arm 68 of follow-up valve 90. This valve controlsthe flow of fluid under pressure from a source 32 to the jack 10. Asuitable type of valve for this purpose is a Vickers two stage meteringvalve, drawing EOCY 10920.

The valve has a follow-up arm I00 connected by the link I02 to thesliding support rod 60 of the levers 50 and 52. Upon movement of valvearm 88 with respect to the valve casing 93, the valve ports are openedand fluid pressure is supplied to cause operation of the jack It. Thismotion of the jack is transmitted through the sliding support rod 60,link I02 and follow-up arm I00 which causes a corresponding rotation ofthe valve casing 90, such movement continuing until the casing resumesits original relationship relative to the valve arm 88. Thus the supportrod is moved an amount directly determined by the movement of valve arm88, and in this position the support rode comes to rest. The movement ofthe support rod causes a deflection of the ailerons to correct for theyaw giving rise to the difference in pressure at the holes 20 and 22.When the yaw is corrected for, the pressures at 20 and 22 become equaland the jack returns the support rod 60 to its neutral position. Thevalve 90 passes the fluid to and from the source 92 to and from the jackI0 via tubes I06, I08, H0 and H2. The valve 28 serves to interrupt or todisable the automatic action which arises from a difference in pressureat the holes 20 and 22. It is desired that this automatic action takeplace only when the stick is in neutral so that when the stick is movedthe control is entirely manual.

The stem I20 of the valve 28 (Fig. 3) is rotatable by gear I22 fixed toit. This gear is turned by the mating gear I24 on the torque tube 32.The gear I24 is larger than valve gear I22 so that only a small angularmovement of the stick is necessary to close the valve to the flow ofpressure therethrough. When the stick is in neutral fluid pressure fromthe hole 20 is transmitted through the valve to tube 25 and to theinterior of bellows 80, while pressure from 22 is transmitted to tube2'! and to the exterior of bellows 80.

The cylindrical valve 28 is shown in Fig. 4. The rotatable valvecylinder I30 has the passage I32 whose ends register with the'openingsinto tubes 24 and 25. The passage I34 is displaced axially rearward frompassage I32 and registers with the openings of tubes 26 and 21. Arotation of the cylinder either way shuts off communication of tubes 25and 2'! with tubes 24 and 26 and instead establishes communication ofboth tubes 25 and 21 with tube I36 open to the atmosphere. Thiscommunication to the atmosphere is established through the branchedpassage I38 and the recesses I40, I42 and I44.

When the pilot moves the stick from neutral, the flow of pressure fromthe holes 20 and 22 is shut ofl? and instead both sides of the bellowsare opened to the same pressure via tube I36 and rod 60 is then underdirect manual control.

Thus if the airplane is side slipping and the pilot wishes to assumecontrol or wishes a stronger restoring moment than the automatic devicewill give, he moves the stick to get this stronger moment and the biasof the ailerons due to the automatic device is eliminated. Thus themanual control, when operated, always has the same restoring effectrelative to the degree of displacement of the stick.

Under automatic operation, when the airplane is flying directly into thewind the pressures at the two holes are equal and no movement of theflaps is called forth. When the airplane is turned directionally theflow of air will be off center of the fuselage and there will be adifference in pressure at the two holes. As long as the stick is ofineutral the device is cut off from the two holes and no automatic changein control results. However, when the stick (or other manual steeringcontrol) is neutralized, the pressures from the holes will produce aresponse which moves the flap differentially to roll the airplane backto the horizontal position.

The tube 32 has fixed to it at one end a detent comprising a plate I50which has a small depression I5I at one spot into which a pin with aspherical end can fit. The pin I52 i pushed toward the plate by thespring I54. The pin registers with the depression when the stick is inneutral and the pilot can tell that the stick is neutralized by theslight resistance to lateral movement of the stick. The resistance isreadily oivercome when the pilot pushes laterally on the s ick.

If the airplane is side slipping, not only should the lift on the lowwing be increased but there should be a yawing moment tending to forcethe low wing forward. Normally an increase of lift is accompanied by anincrease in drag, the induced drag which arises with an increase oflift. If a yawing moment tending to push the low wing forward is notpresent the airplane will be turned in yaw in the wrong direction whichwill endanger the airplane.

In accordance with this invention a depression of the aileron, such asI6, enlarges the slot I60 (Fig. 5) between the upper surface of theaileron and the wing main body surface I62 so that a greater jet of airis discharged to produce a thrust. Such an aileron and wing main bodyconstruction is disclosed in my U. S. Patent No. 2,406,919 datedSeptember 3, 1946. The jet for the wing slot is supplied by the blowerI66 suitably driven from the engine in the nacelle I68,

ing moment would be the use of a drag producing element projected intothe relative wind by the up aileron such as a spoiler.

The air pressure openings can also be located on other parts of theaircraft besides the fuselage. For instance, an advantageous place isnear the tips of the wing, the wing being considered in this inventionas including the lifting surfaces between the wing tips on oppositesides of the fuselage or longitudinal center line of the aircraft. Theopenings in this case are displaced laterally a. substantial amount withrespect to the center of gravity of the aircraft in which position theyare similarly sensitive to the turning of the aircraft. Further, theopenings may be made responsive to the direction of the relative wind aswell as to its pressure.

As shown in Figs. 6 and 7, the tubes 24' and 26' lead to spanwise spacedholes I96 and I98 in the upper surface of the wing and to the sameconnections on valve 28 as the tubes 24 and 26. In normal straightflight the pressure distribution along a spanwise line 11 is shown bycurve 200 while if the airplane is side-slipping, the pressuredistribution is shown by curve 202. In the latter case the windward tipedge of the wing acts like a leading edge and increases the suctionabove the wing. The change in pressure difference between the two holesactuates the bellows BI] and associated mechanism as previouslydescribed.

While the forms of apparatus herein described constitute preferredembodiments of the invention, it is to be understood that the inventionis not limited to these precise forms of apparatus,

Another method of creating a favorable yawand said lift varying meansfor direct actuation of said lift varying means by said manual controlindependently of said power actuating element.

2. In combination in an aircraft having a supporting wing with means tovary the lift thereof differentially on opposite sides of the aircraft,a lever for effecting movement for said lift varying means, a poweractuating means connected at one point to said lever, a manual controlhaving a neutral position and connected at another point to said lever,a device responsive to a change in the direction of the relative wind,automatic means connected to said power actuating means and controlledby said relative wind direction device for effecting movement of saidlever to adjust said lift varying means with said manual cont-r01remaining in said neutral position, and means connected to said manualcontrol for disabling said automatic means in response to movement ofsaid manual control away from said neutral position for direct movementof said lever by manual operation independently of said automaticcontrol.

3. In combination in an aircraft having a supporting wing with means tovary the lift thereof differentially on opposite sides of the aircraft,a lever for effecting movement for said lift varying means, a poweractuating means connected at one point to said lever, a manual controlhaving a neutral position and connected at another point to said lever,a device responsive to a change in the direction of the relative wind,automatic means connected to said power actuating means and controlledby said relative wind direction device for effecting movement of saidlever about j the connection point with said manual control as and thatchanges may be made therein without departing from the scope of theinvention which is defined in the appended claims.

What is claimed is:

1. In combination in an aircraft having a supporting wing with means tovary the lift thereof differentially on opposite sides of the aircraft,the

combination of a manual steering control having a neutral position andadjustable away from said in said neutral position, means operablyinter-j connected with said manual steering control and a pivot toadjust said lift varying means with said manual control remaining insaid neutral position, and means connected to said manual control fordisabling said automatic means in .re-

, sponse to movement of said manual control away with said winddirection device and operable in from said neutral position for directmovement of said lever by manual operation about the connection pointwith said power actuating means as a pivot independently of saidautomatic control.

EDWARD A. STALKER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,956,755 Constantin May 1, 19341,972,336 Gardner Sept. 4, 1934 2,029,700 Boykow Feb. 4, 1936 2,343,288Fink Mar. 7, 1944 2,394,384 Horstmann Feb. 5, 1946 2,420,932 CorneliusMar. 20, 1947 2,464,629 Young Mar. 15, 1949 2,471,821 Kutzler May 31,1949 2,499,471 Dunning Mar. 7, 1950

